Applications deployed in a production environment must coexist in a common runtime environment, which is the operating system in which they have been installed. However, the installation of a new application typically damages an existing environment. As a result, already-tested applications can potentially conflict. Thus, greater IT resources are required to validate a production environment every time a new product is installed thereto or patched.
This may be addressed by using virtualization technology at the operating system level, e.g. VMWare. There are currently a number of products available like IBM Progressive Deployment System (PDS) (http://web.opensource.ibm.com/www/pds/) that use an application virtualization approach. Under this approach, while deployed applications share operating system and hardware settings with other applications, they also run in a virtual environment, working on their own private virtual files, directories and registries that define the application environment.